1. Field of the Invention
The Present invention relates generally to video-ready Internet telephones, and more particularly to a video-ready Internet telephone which can be separately used as a VoIP (Voice-over Internet Protocol) telephone and also used as an MoIP (Multimedia over Internet Protocol) telephone at a low cost while utilizing peripheral equipment.
2. Background of the Related Art
The VoIP solution for providing a voice communication service over the Internet has been widely spread centering on enterprises. Such a VoIP solution enables a user to make a domestic or overseas phone call at a low call charge. Recently, with the development of an Internet infrastructure, the VoIP-based telephone call has performance which is not behind a general telephone call in terms of voice quality.
Internet-based communication has the advantage of exchanging multimedia in addition to a cost-saving effect. While making an Internet-based telephone call, a user can exchange character information or video information. There has been a growing need for a video call because users can talk over the phone while watching each other. Cellular phones supporting a digital communication already equip themselves with cameras to provide a video call service.
The demand for a video call is directed toward a future VoIP solution. However, there are significant obstacles to support a video call as already known in a cellular phone service.
First, a service cost is high. Video data needs a wider bandwidth as compared with audio data. For a natural video call, a bandwidth of approximately 600 Kbps or more should be stably supported in two-way. Thus, since the video data occupies a wide bandwidth, much more service cost is inevitably charged for the transmission and reception of the video data in comparison with the audio data. If the cost is charged by packet, i.e., the data transmission/reception unit, the whole communication charge is increased up to ten times or more the current call charge.
Second, a currently established infrastructure is unstable to support the video call. With the spread of the Internet, the performance or capacity of a network system has been improved and an ambient environment where users can access the Internet has also been improved. However, with an increase in the number of Internet users and in real-time media communication applications, a need for network bandwidth capacity has also been increased. Therefore, it is not easy to secure enough capacity of the Internet accessible by users to endure real-time communication applications such as Internet games, chatting, VoIP, MoIP, etc. In this case, there may occur data loss, delay or severe jitter in the course of communication due to the property of an Internet protocol, thereby causing inappropriate real-time video communication. This is a serious factor by which users are dissatisfied with quality of service.
Third, the price of a video telephone is high. To support video communication, a camera and a liquid crystal display (LCD) with a color screen should be provided in addition to telephone equipment. These components are main items which contribute to an increase in the price of the video telephone. The high price is a serious factor in widely spreading the video telephone market.
The present invention is intended to provide a low-priced telephone having a video call function. In more detail, the inventive telephone has a hardware architecture in which a processor for enabling users to make a video call is provided but a camera and an LCD are not equipped. The inventive telephone is basically used as a VoIP telephone and supports a video call function if it is connected to an external camera and LCD via external input and output ports. Hence, a hardware structure becomes simpler and a small-sized outer appearance suitable for mobility is achieved. First of all, the manufacturing cost of a product can be lowered. A user can select a voice call or a voice/video call according to user networks or ambient environments, thereby satisfying the various needs of the user.
The structure and operation of currently used telephones will now be described hereinbelow.
<Internet Telephone Protocol>
Internet telephones use a standard protocol defined by international standard organizations such as H.323 (International Telecommunications Union, ITU) and SIP (Internet Engineering Task Force, IETF). The Internet telephones may have somewhat different architectures according to each hardware and protocol but usually have the following software configuration. FIG. 1 shows a configuration of the typical Internet telephone.
Referring to FIG. 1, a user interface, an information service module, a telephony signaling gateway, a media module control part, a system service part, a network interface (I/F) protocol part, and a media processing part are mutually-organically connected to an application main part.
A VoIP telephone carries out communication by exchanging information on preset a calling party's voice processing capability and a called party's voice processing capability while a call is established between the two parties and determining a proper voice CODEC (Coder/Decoder). Similarly, an MoIP telephone performs communication by exchanging information on preset a calling party's voice/video processing capability and a called party's voice/video processing capability while a call is established between the two parties and determining a voice/video processing scheme.
<VoIP Telephone>
The VoIP telephone refers to a telephone intended for only a voice call among Internet telephones of a hardware construction. The VoIP telephone has the same construction as a general Public Switched Telephone Network (PSTN) telephone in both their outer appearances and operating methods. Therefore, a general telephone can be replaced by the VoIP telephone with a low call charge.
The VoIP telephone includes, as shown in FIG. 2, a main processing module 11, a voice processing module 12 for processing voice, a voice input/output (I/O) module 13 such as a handset, a speaker, etc., and a network module 14 connected to the Internet. The VoIP telephone also includes an LCD 16 or a light emitting diode (LED) for setting and displaying the state of the telephone, a keypad 15 for key input, an external I/O interface 17, and a power module 18.
<MoIP Telephone>
The MoIP telephone refers to an Internet telephone supporting video communication, which is an improved type of the VoIP telephone. As illustrated in FIG. 3, in the MoIP telephone, a video processing module 20 for processing video data and a video I/O module 30 for processing the input/output of video devices such as a video camera, an LCD, etc., are added to the construction of the VoIP telephone.
In some cases, the video processing module 20 is software-processed by the main processing module 11. However, a dedicated video processor is separately constructed to process images of high performance. Due to such hardware configuration, the price of the MoIP telephone is higher than that of the VoIP telephone. Especially, the camera and LCD are the main cause of raising the product cost.
The detailed construction of the video processing module 20 of the MoIP telephone is shown in FIG. 4. The video processing module 20 includes a video CODEC 21, a video pre-processor 22, and a video post-processor 23. The video processing module 20 converts a digital video signal into an analog video data to output the converted analog signal through the video output module, or converts an analog video signal applied thereto from the video input module into a digital signal. Further, the video processing module 20 compresses video data according to a used compression CODEC.
FIG. 5 shows a detailed construction of the video I/O module 30 of the MoIP telephone. The video I/O module 30 includes a video input processor 31, a camera 32, a video output processor 33 and an LCD 34. The video I/O module 30 receives an analog video signal from the camera 32 or receiving the converted analog video signal from the video processing module 20 to display corresponding analog video data in response to the received analog video signal on the LCD 34.
The conventional VoIP telephone has already come into wide use at a low cost, but the MoIP telephone has not in terms of various Internet environments, a service cost, a product price, etc.
In the present invention, since only a video processing module is added to the existing VoIP telephone, a terminal price can be reduced to the level of the VoIP telephone. Moreover, a voice call or voice/video call can be manually or automatically made by using one terminal according to the user environment.